Detachable Holding Tank: 5.3 gallon holding tank is detachable for easy emptying. Detachable Holding Tank: 5.3 gallon holding tank is detachable for easy emptying. Pump Flush: Fresh water holding tank utilizes a pump flush action to effectively rinse the bowl of the toilet; Flush Capacity: 4-gallons. Sturdy Construction: Made of durable ABS resin. Size: Measures 17 1/8-inches (H) x 16 5/16-inches (W) x 18 5/8-inches (D); The outside width of the seat measures 12 5/8-inches the inside width is 8 13/32-inches. Weight: Weighs approximately 11.7 lb. when empty and 56 lb. when full.